Respiratory syncytial virus, or RSV, causes an infection of the lungs and breathing passages, and is a major cause of respiratory illness in babies and young children. According to Nemours Health Care System, almost all kids are infected with RSV at least once by the time they are 2 years old. Sometimes, this illness can lead to complications as the child gets older.
Breathing Difficulties
A baby with an RSV infection can develop severe breathing problems that need to be observed and treated in the hospital. An RSV infection in infants born prematurely--before 36 weeks gestation--who have chronic lung, heart or immune problems, is more likely to be severe. Any baby under 6 months old who develops RSV should be watched closely by his doctor, as symptoms tend to worsen quickly. In rare cases, if the virus goes untreated, RSV can be fatal.
Asthma
Asthma is a condition of recurring episodes of wheezing or coughing and difficulty breathing in a child with no other lung problems. According to the RSV Info Center, there is some evidence that asthma has been identified in children 10 years after contracting an RSV infection in infancy. This may have been caused by the early infection damaging the immature lung.
Other Illnesses
Bronchiolitis is swelling and mucus buildup in the smallest air passages in the lungs, and is caused by the RSV virus. According to the U.S. National Library of Medicine, the RSV virus can also cause croup, a breathing difficulty characterized by a barking cough; ear infections; or pneumonia.
